:root{--ink:#1a1a18;--ink-soft:#4a4a45;--paper:#f7f7f4;--card:#fff;--teal:#00733a;--teal-dark:#04511f;--teal-pale:#e1f3e7;--amber:#c98a3b;--amber-pale:#f6eada;--rose:#b4483c;--rose-pale:#f7e8e5;--brand-red:#ce1126;--brand-red-pale:#fbe7e9;--line:#e1e0d9;--line-soft:#edece6;--radius:4px}*{box-sizing:border-box}html,body{margin:0;padding:0}body{background:var(--paper);color:var(--ink);-webkit-font-smoothing:antialiased;font-family:IBM Plex Sans,sans-serif;font-size:15px;line-height:1.55}h1,h2,h3,h4{color:var(--ink);margin:0 0 .4em;font-family:"Source Serif 4",serif;font-weight:600}a{color:inherit;text-decoration:none}button{cursor:pointer;font-family:inherit}.nav-link{color:var(--ink-soft);font-weight:500;transition:color .15s}.nav-link:hover{color:var(--teal)}.btn{border:1px solid var(--teal);background:var(--teal);color:#fff;letter-spacing:.02em;border-radius:2px;align-items:center;gap:8px;padding:11px 22px;font-size:13.5px;font-weight:600;transition:background .15s,color .15s,border-color .15s;display:inline-flex}.btn:hover{background:var(--teal-dark);border-color:var(--teal-dark)}.btn.secondary{color:var(--teal);background:0 0}.btn.secondary:hover{background:var(--teal-pale)}.btn:disabled{opacity:.4;cursor:not-allowed}.wrap{max-width:1080px;margin:0 auto;padding:44px 32px 80px}.wrap.narrow{max-width:560px}.wrap.wide{max-width:1100px}.course-grid{grid-template-columns:repeat(2,1fr);gap:20px;display:grid}.lesson-layout{border:1px solid var(--line);background:var(--card);border-radius:4px;grid-template-columns:250px 1fr;display:grid;overflow:hidden}.lesson-nav{background:var(--paper);border-right:1px solid var(--line);padding:22px 0}.lesson-content{padding:38px 44px}.inbox-layout{border:1px solid var(--line);background:var(--card);border-radius:4px;grid-template-columns:280px 1fr;height:520px;display:grid;overflow:hidden}.inbox-threads{background:var(--paper);border-right:1px solid var(--line);overflow-y:auto}.form-grid-2{grid-template-columns:1fr 1fr;gap:16px;margin-bottom:16px;display:grid}@media (max-width:780px){.lesson-layout{grid-template-columns:1fr}.lesson-nav{border-right:none;border-bottom:1px solid var(--line);max-height:240px;overflow-y:auto}.lesson-content{padding:26px 20px}.inbox-layout{grid-template-columns:1fr;height:auto}.inbox-threads{border-right:none;border-bottom:1px solid var(--line);max-height:220px}}@media (max-width:640px){.course-grid,.form-grid-2{grid-template-columns:1fr}}@media (max-width:480px){.wrap{padding:28px 18px 60px}}.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:24px}.course-card{border-top:3px solid var(--card-accent,var(--line));transition:border-color .15s,box-shadow .15s,transform .15s}.course-card:hover{border-color:var(--line);transform:translateY(-2px);box-shadow:0 6px 20px #1a1a1814}.course-card h3{transition:color .15s}.course-card:hover h3{color:var(--teal-dark)}.input{border:1px solid var(--line);background:var(--card);width:100%;color:var(--ink);border-radius:2px;padding:12px 14px;font-family:inherit;font-size:14.5px}.input:focus{border-color:var(--teal);outline:none}.mono{font-family:IBM Plex Mono,monospace}